My network is already set up and has been working for "a while". I have wifi and wired internet on a bunch of devices and stations (more than I care to admit), the gigabit router is working and configured. Everything is wifi g or 100mbit or newer. I recently reloaded windows on 3 of the most used stations.

My cap to the internet is 16mbit/1mbit which I just ran off of speedtest.net (and realize that i need to bang on TW for not giving me anything close to 50 like I'm supposed to have). Everything can be running like netflix, steam games, bittorrent, etc etc, concurrently and there's no problems.

But when I go to copy files from one station to another, I can never seem to crack 20mbit. It doesn't cap at 20mbit (I watch using the excellent networx http://www.softperfect.com/products/networx/), it vacillates up and down and never quite seems to manage ~20mbit. On some stations it never even gets close to that even tho I have no 10mbit nics in the house.

Right now I'm copying my library of music production source files from a pc to laptop. The files vary in size from a couple megs to a couple gigs. And I realize that copying 1k * 2mbyte files will be significantly slower than 1 * 2gbyte file, but even on the big files, it doesn't pick up. But between to gigabit nics, wired, I would expect it to be >20x the current speed.

I would expect that, even between 2 wireless g devices, I could get > 40mbit with the tech cap being 54mbit, and that between 2 gigabit stations, that i could get > 500mbit (reviews say they got 700 consistently)

Note: I'm not trying to get 100% advertised speed. I know that's not really attainable in windows. I would just like to use the tech that I have on my machines.

This has been a consistent problem for as long as I can remember, spanning routers, windows reloads and various devices with the only constant being my home office work pc... and even it's only constant for a couple years. This is actually the reason I bought this router like a year ago. However today it finally got on my nerves when the file copy is telling me 4 days.


I found and ran j/iperf between the 2 machines. TCP wouldn't work, but UDP did. Max cabled speed: 275 mbit. Max wifi <> desktop speed: 275mbit. That is exactly the sata drive to drive speed I get on the desktop, ~33mbyte/s, but iperf is supposed to eliminate the drive factor. I can however confirm that neither drive thrashed. Not exactly the speed I'd like to have, but it's like 12x what I'm getting. I can't for the life of me believe that there's a 92% overhead between a lab test and real world use.

I also checked powersave/green/EE settings and turned off a couple of them. Managed to gain about 5% speed in iperf.

But I did find a solution . . .

  • What type of wireless access points, what type of switches? I've seen 100mb switches choke on < 20mb/s of traffic when it is High PPS. Most "cheap" and heck some expensive switches seem to only get those speeds when dealing with IMIX, or all 1500 byte frames, start sending tons of little packets and they slow way down Also have you checked and verified your Cables. Since bad cable can lead to slow speeds (especially with TCP due to Retransmits, etc..). Also perhaps look at iperf to run udp speed tests..
    – Doon
    Commented Aug 21, 2013 at 1:51
  • 1
    Your question is very hard to understand there is a lot of trivial information not directly connected to the question
    – Ramhound
    Commented Aug 21, 2013 at 2:22

5 Answers 5


I don't wish to sound rude, but make sure you are thinking in MBit/s and not the MBytes/s that the Windows File Copy displays. If you are transferring at 20 MBytes/s on a Wirelesss G connection, you are doing pretty good. 20 MBytes/s isn't bad for a 100 MBit in home LAN.

  • 1
    Not rude at all, just basic troubleshooting. I am however not using windows explorer for the filecopy (total commander) and am using another 3rd party app for monitoring. TC shows ~2.4mbyte/sec, Networx shows ~20mbit/sec. The potential confusion you voice is why I spelled it out everytime in the OP.
    – monsto
    Commented Aug 20, 2013 at 19:49
  • Is your file transfer to/from a wireless device? Are you measuring from a safe boot with networking? There are many other items on the computer that can silently hog bandwidth other than the file copy. Try using ProcMon and see what else is running. Do you have a spare router to try and see if your router is causing some of the problem? Try removing all devices from the network except the sending computer and the receiving and make sure that both are in Safe Mode with networking turned on (Assuming Windows) and see if that has any effect. Commented Aug 20, 2013 at 19:55

If your lawnmower doesn't work, don't immediately take it to the shop . . . FIRST check to see if there's gas.

If transfer rates between stations on your home network seem really slow, make sure they're both running wired to the router before you say they are.

I've no idea when it happened (perhaps the wife one day when she was working from home? yeah, i'll blame her) but it seems that my desktop wasn't running wired like I thought. Once I fixed that, the connection has since topped out at 811mbit and averages 365mbit (on 10s of Ks of files of varying sizes). From 4days to < 1hr. Yaay.

That stations wifi is supposed to be n so it's probably misconfigured. doesn't matter, I shouldn't have been using it anyway since it's literally 2 feet from the router. Thanks for the responses.


Sounds like you need to grind down and iteratively test everything until you find the source of a problem.

One thing to keep in mind is that a busy network will be slower than an idle network so if your other machines are torrenting or doing other things it will make things slow.

Start with the least number of variables possible: laptop A connected directly to laptop B, no router in between (assign a static IP to both ends) and transfer a file. Remember 1000Mbit/sec = 125MByte/sec. Remember also that unless you have an SSD that is otherwise idle you probably aren't going to get more than 60MByte/sec under the best conditions. Also if your stuff is on external drives, know that USB slows down things a lot unless you have USB 3.0. Also make sure your power settings aren't throwing your NICs into 10Mbit mode (this is a feature of at least some Intel NICs).

Once you work on getting two machines transferring fast, you know then they aren't the issue. Connect them to your gigabit router next, and try more transfers through your two known working machines, and see what changes. Tweak settings until you get the best speed possible. Then add your wireless and do the same.

  • I like how you say "grind down" as if you knew it was something I didn't want to do. Congratulations, you've graduated from the Uri Gellar School of Clairvoyance.
    – monsto
    Commented Aug 21, 2013 at 6:18

For your WIFI - I believe the problem is that you - like me - expect that when equipment advertises a maximum speed (eg 54 megabit for 802.11g) your expectation is that it is actually possible to get that speed. Its not - unless you are in a lab [ I assume with the aerials touching] See here, here here (last paragraph)

In essence I guess this means upgrade your WIFI equipment to vendors who lie to you about giving you 300 Megabit speed rather then vendors who lie about giving you 54 megabits. I upgraded from 802.11g to 802.11n dual channel (and also dual band), and my speed went up about 7 times - 802.11n is a worthwhile upgrade

There are some other things you may be able to do to get a bit better performance, like turning off encryption (but of-course that opens a new can of worms), changing your frequencies, ensuring 802.11b is disabled if all your devices are 802.11g, moving your AP to a more central point.

For your Gigabit connections

If they are directly connected to the same switch, yes, you should be able to get close to the advertised speeds - if your equipment can handle it (I have had hard drives which were slower then the network speed). If your gigabit ports connections are going through the a device other then a gigabit switch you will probably find the number of packets forwarded per second is constraining your performance - this was the case for me when I had WIFI and 100 megabit devices in a router rather then a switch - the WIFI router couldn't push packets fast enough, even on the same subnet between wired ports. Also, check your cables. If your cables are not high quality, you will probably be getting quite a bit of loss [ although I'd hope to get more then 40 megabit through them ]

  • "advertised speed" is kinda like "0% down (with approved credit)" which basically means "in a perfect world". I just wish i was getting something more than 2% efficiency.
    – monsto
    Commented Aug 21, 2013 at 3:43

The bandwidth mentioned in wireless protocols includes the data, header (more than wired), acks (and their headers), failed packets due to collision, retransmitted packets (data + header), control packets, etc. And also since the medium is shared any other device sending any other packet will take up the bandwidth (causing collision, retransmission, etc). So in practice, 20mbps is pretty decent for wireless G. External interference also can cause collisions and reduce speed. Upgrading from g to n or a is really useful.

Since you also mention the wired ports show the same symptoms, the problem could be in the router (advertised as gigabit router, but internal switching speed cannot handle that or buggy or some misconfiguration that is limiting the traffic) or in the hard drive speeds (either in the source or in the destination) or in the software that does the copy (total commander in your case).

I wish for a software that can test the speed within the home network (eliminating hard drive speed limitations, etc).


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